JPH02162283A - Digital beam forming radar - Google Patents

Abstract

PURPOSE:To enhance jamming-resistant capacity by changing over the transmitting direction of a transmitting radio wave while taking the synchronism of operation timing and cylindrically changing over the transmitting radio wave at each time when the transmitting direction is changed over in synchronous relation to the change-over of said transmitting direction. CONSTITUTION:As a transmitting antenna, a phased array antenna 1a is used and, as a receiving antenna, a digital beam forming antenna 7 is used. The antenna 7 consists of a plurality of antenna elements 1b, 3, a receiver 4 discriminating receiving frequency provided at every antenna element and an operator 6. The output at every filter of a filter bank is converted to a digital signal by each A/D converter 5 and the operator 6 inputs the digital signal from the A/D converter 5 to apply operation thereto and discriminates receiving radio waves from different directions at every directions. A timing controller 15 controls the operation timing of a scanning beam controller 2a, a frequency synthesizer 2b and the converter 5 to take synchronism and cyclically changes transmission frequency at every transmitting direction to control the same.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention applies non-scanning digital beamforming (Digital B
The present invention relates to a DBF radar using a DBF (eam forming) antenna, and particularly to improving its anti-jamming performance.

[Prior Art] FIG. 5 is a diagram showing a schematic configuration of a conventional DBF radar and a jamming device mounted on a target, etc. monitored by the radar. In the figure, +11 is a wide-angle beam transmitting antenna;
(2) is a transmitter for transmitting radio waves of frequency F into space from the transmitting antenna (1). (3) is a plurality of antenna elements arranged in a − dimension or two dimensions; (4)
is provided for each antenna element (3).
), (5) is a receiver that receives radio waves via (
4) The signal output from the receiver (4) is A
/D conversion A/D converter, (6) is each A/D converter (
5) inputs multiple digital signals transferred simultaneously and performs DFT (Digital Fourie
r Transform: A beamformer (calculating means) that performs digital Fourier transform, distinguishes received radio waves from different directions for each direction, and outputs them to the outside. A square beam, non-scanning DBF antenna (7) is constructed and used as a receiving antenna.

On the other hand, (8) is E S M (El
ect-ronic 5upport Measure
), (9) is a radar wave analysis device called E CM (
Electronic Counter Meas-u
interference wave generators called re), (10), (11
) are the receiving antenna and transmitting antenna on the jammer side.

The radar wave analysis device (8) has a receiving antenna (10)
A channelized receiver (12) that receives only predetermined radio waves from among the radio waves captured by The signal analyzer (14) consists of a signal waiting trace amount extractor (13) to extract, and a signal analyzer (14) which analyzes the signal from the feature quantity output from the signal waiting trace amount extracting machine (13). Based on the information from the radar, the interference wave generating device (9) generates interference waves equivalent to radar waves, and transmits them via the transmitting antenna (11).

Next, the operation will be explained.

On the DBF radar side, the wide-angle beam transmitting antenna fil
is used to transmit radio waves of frequency F□ over a wide range. Further, the reflected echoes that hit the target and return are received using the DBF antenna (7), and the reflected echoes are sent to each antenna element (3), receiver +41. A/D converter (
5) into a beamformer (6), performs Fourier transformation, and outputs the received radio waves from different directions by discriminating them in each direction to obtain information such as the position and velocity of each target object. D
The BF antenna (7) uses multiple narrow angle beams without scanning, that is, it can simultaneously form multiple narrow angle beams in space, and can distinguish multiple reflected echoes of frequency F1 received simultaneously from different directions in angular directions. .

On the other hand, on the target side, a channelized receiver (12) receives radar waves via a receiving antenna (10), and a signal waiting trace amount extractor (13) extracts the characteristics of the radar waves. Pulse width 2 output from the micro extractor (13)
The radar waves are analyzed by a signal analyzer (14) based on frequency, pulse amplitude, etc. When the radar waves are analyzed, the interference wave generator (9) generates interference waves equivalent to the radar waves and transmits them to the DBF radar side via the transmitting antenna (11).

[Problems to be Solved by the Invention] The conventional DBF radar is configured as described above, and because it transmits radio waves of a specific frequency F over a wide range, the transmission of radio waves cannot be easily detected by the other party's ESM. As a result, there was a problem in that it was susceptible to interference by radio waves having the same frequency F1 as the transmitted radio waves.

This invention was made to solve the above problems, and it is a DBF that can improve anti-jamming performance.
The purpose is to obtain radar.

[Means for Solving the Problems] A DBF radar according to the present invention uses a phased array antenna as a transmitting antenna, a plurality of antenna elements as a receiving antenna, and a filter bank provided for each antenna element to discriminate reception frequencies. an A/D converter provided for each filter of the filter bank to A/D convert the output, and a plurality of digital signals simultaneously transferred from each A/D converter. A digital beam forming antenna is used, which includes a calculation means that performs a predetermined calculation and discriminates received radio waves from different directions for each direction, and beam scanning control that scans transmission from the phased array antenna with a single narrow angle beam. a frequency synthesizer capable of switching the oscillation frequency provided as a transmission radio wave generation source from the phased array antenna, and controlling the operation timing of the beam scanning controller, frequency synthesizer, and A/D converter to synchronize them. and a timing controller that periodically switches the transmission frequency for each transmission direction.

[Operation] In this invention, a phased array antenna is used as a transmitting antenna, and the timing controller synchronizes the operation timing of each A/D converter of the beam scanning controller, two-frequency synthesizer, and DBF antenna, thereby achieving high-speed transmission. The narrow-angle beam is scanned to switch the transmission direction of the transmission radio waves, and each time the transmission direction is switched, the transmission frequency is periodically switched in synchronization with the switching.

[Example code] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the overall configuration of a DBF radar according to an embodiment, and in the figure, (la) indicates a plurality of antenna elements (1b) and a phase shifter provided for each antenna element (lb). It is a well-known phased array antenna as an antenna that can electronically scan the beam at high speed, and is used as a transmitting antenna. (2a) is a beam scanning controller that scans the transmission from the phased array antenna (1a) with a single narrow angle beam, and (2b) is an oscillation frequency provided as a transmission radio wave generation source from the phased array antenna (1a). Switchable frequency synthesizer (2c) is the frequency synthesizer (2b)
), a power divider (15) that distributes the output from the phased array antenna (1a) to each antenna element (1b);
is each A/D converter (of the beam scanning controller (2a), frequency synthesizer (2b), and DBF antenna (7)).
5) is a timing controller that controls the operation timings and synchronizes them, and is composed of a microprocessor or the like, and control to periodically switch the transmission frequency for each transmission direction is realized by a program.

FIG. 2 is a detailed configuration diagram of each receiver (4) in the DBF antenna (7) used as a receiving antenna.
In the figure, (41) is an amplifier that amplifies the output of each antenna element (3), (42) is a power divider that distributes the output power of the amplifier (41), and (43) is a power divider (42).
A plurality of (here, five filters with frequencies F and ~F) extracting signals of predetermined frequency components from the output of the filter (43a).
Each filter (43a) is a filter bank consisting of
An A/D converter (5) is provided for each receiver, and one receiver (4
) is connected to a plurality of (five in this case) A/D converters (5).

Moreover, FIG. 3 is a configuration diagram showing the details of the connection between each receiver (4), A/D converter (5), and beamformer (6), and as shown in the figure, each receiver (4) The outputs of each are input to a plurality of A/D converters (5), and each A/D converter (
The outputs of 5) are configured to be transferred to the respective beamformers (6).

Next, the operation will be explained.

When transmitting radio waves to a target via a phased array antenna (1a), a timing controller (15) is used to control a beam scanning controller (2a) and a frequency synthesizer (2b).
Controls and synchronizes the operation timing of each A/D converter (5) of the DBF anti-switch (7), scans the narrow angle bead 11 at high speed, switches the transmission direction, and transmits the transmission radio wave. , the transmission frequency is periodically switched in synchronization with each switching of the transmission direction. For example, when monitoring a certain range as shown in Figure 1, this range is Ott 02
1031 (Divided from 7410S, as shown in Fig. 1 and Fig. 4, frequency F 1. Frequency Fat for transmission direction θ2, frequency F3. For direction 04, frequency F4° is assigned, and for transmission direction Oh, frequency F5 is assigned.Then, while sequentially switching and scanning from transmission direction θ to transmission direction OS, the frequency is changed to Fl-4F2→F.

→ F4 → F6 will be switched every 74 years.

By doing this, if there is an ES in the transmission direction θ4,
Even if M were to arrive, only radio waves of frequency F4 would be transmitted in this direction, so interference would be received from the direction of 04 with radio waves of frequency F4. At this time, echoes from the target in the 04 direction cannot be received, but echoes received from other directions have a different frequency from the interfering waves, so they are not affected at all.

On the other hand, the echoes that hit the target and return are received first by each antenna element (3) of the D B F' antenna (7).
The signal captured by the filter bank (43) in the receiver (4)
) for each frequency F8 to F5, and the discriminated signals for each frequency F8 to F5 are A/D converted by an A/D converter (5). Then, each A/D converted frequency F1
~F, corresponding beamformer (6) for each signal
Fourier transform is applied to each direction θ, ~0. Discriminates and outputs each echo. At this time, the timing controller (
15), the beam scanning controller (2a) performs scanning in transmission directions 01 to 06, the frequency synthesizer (2b) performs switching between frequencies F and ~Fs, and the DI3F antenna (
The operation timing of the A/D conversion performed by each A/D converter (5) in 7) is controlled and synchronized.

[Effects of the Invention] As described above, according to the present invention, a phased array antenna is used as a transmitting antenna, and a plurality of antenna elements and a filter bank provided for each antenna element to discriminate reception frequencies are used as a receiving antenna. an A/D converter provided for each filter of the filter bank to A/D convert the output, and a plurality of digital signals simultaneously transferred from each A/D converter. A beam scanning controller that uses a digital beam forming antenna consisting of a calculation means that performs a predetermined calculation and discriminates received radio waves from different directions for each direction, and scans the transmission from the phased array antenna with a single narrow angle beam. , a frequency synthesizer capable of switching the oscillation frequency provided as a transmission radio wave generation source from the phased array antenna, and controlling the operation timing of the beam scanning controller, frequency synthesizer, and A/D converter to synchronize them. , and a timing controller that periodically switches the transmission frequency for each transmission direction, the effect of improving anti-jamming performance can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention, FIG. 2 is a detailed configuration diagram of a receiver in the embodiment, and FIG. 3 is a diagram showing a receiver, an A/D converter, and a beamformer in the embodiment. FIG. 4 is a detailed configuration diagram showing connection relationships, FIG. 4 is a signal waveform diagram showing transmission and reception timing in the embodiment, and FIG. 5 is an overall configuration diagram showing a conventional example. (1a) is a phased array antenna, (lb), +
31 is an antenna element, (2a) is a beam scanning controller,
(2b) is a frequency synthesizer, (2c) is a power divider, (4) is a receiver, (5) is an A/D converter, (6) is a beam former (calculating means), +71 is a DBF antenna, (15) ) is a timing controller, (41) is an amplifier, (42) is a power divider, (43) is a filter bank, and (43a) is a filter. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Agent Masuo Oiwa (2 idiots) 1. Indication of the case 20. Name of the invention 3. Letter of amendment (spontaneous) Japanese Patent Application No. 63-317770 Digital Beam Forming Radar 5 Detailed explanation of the invention subject to amendment , drawing column. G Contents of the amendment (1) In the 8th line of page 2 of the specification, the phrase ``without scanning'' is amended to ``form.'' (2) On page 4, line 18 of the same book, “no scanning, that is.”
Correct the phrase ", that is," to mean ", that is." (3) In the same book, page 8, lines 18 to 19, the phrase ``output power'' is corrected to ``output signal.'' (4) The drawings and Figure 3 shall be amended as shown in the attached sheet. Representatives

Claims (1)

[Claims] Using a phased array antenna as a transmitting antenna,
As a receiving antenna, a receiver is provided with a plurality of antenna elements, a filter bank provided for each antenna element to discriminate the reception frequency, and an A/D converter provided for each filter of the filter bank to A/D convert the output. /D converter,
A digital beamforming antenna is used, which comprises a calculation means that inputs a plurality of digital signals simultaneously transferred from each A/D converter, performs predetermined calculations, and discriminates received radio waves from different directions for each direction, and a beam scanning controller that scans the transmission from the phased array antenna with a single narrow angle beam; a frequency synthesizer capable of switching the oscillation frequency provided as a transmission radio wave generation source from the phased array antenna; A digital beamforming radar comprising: a timing controller that controls and synchronizes the operation timing of a synthesizer and an A/D converter, and periodically switches a transmission frequency for each transmission direction.